Amargasaurus cazaui — a sauropod with spines
This bizarre-looking sauropod was found in Patagonia, Argentina, in 1984. Amargasaurus was one of only three members of the dicraeosaur family. It was smaller (between six and 10 metres long) and had a shorter neck than most sauropods. Recent research suggests that the dicraeosaurs were a group of sauropods that browsed close to the ground, which is reflected in their size.
Amargasaurus had two rows of distinctive spines along its neck, back and tail. These were almost certainly used for defence, especially the ones on its neck, which were sharp. Some of the spines may also have supported a sail of skin, which could have assisted the animal to regulate the temperature of its blood. The spines or a sail could also have been used for display in mating rituals, to warn off a rival or even to signal to other animals in the herd.